Health Officials Urge Early Flu Vaccination as Cases Rise

Health officials across the United States and Canada are encouraging people to receive influenza vaccinations earlier than usual as seasonal flu activity increases in several regions. Reports published October 7-9, 2026, describe unusually early increases in infections, particularly in western North America and major Canadian cities, although experts say it remains too early to determine whether the 2026-27 season will be unusually severe.

Data from Epic Research show that influenza-related encounters reached 140.6 per 100,000 patients during the week of September 13, 2026, the highest mid-September level in the post-pandemic period. The rate was approximately twice the levels recorded during the same week in 2024 and 2025, when encounters reached 76.8 and 65.6 per 100,000 patients, respectively.

Epic Research also recorded a 1.5% influenza test positivity rate that week, exceeding the corresponding mid-September figures of 0.8% in 2022, 0.9% in 2023, 0.6% in 2024 and 0.5% in 2025. The organization said rising encounters and positive tests across outpatient, emergency department and inpatient settings indicate increased influenza activity.

In Canada, national surveillance data covering the period through September 26 recorded 2,102 influenza detections since the end of August. According to CBC News, 3.7% of influenza tests were positive during the week of September 20-26, compared with an average of 0.5% for the same period in 2023-2025.

Approximately 98% of laboratory-confirmed Canadian cases involved the H1N1 strain, according to government figures cited by CBC News. More than 400 confirmed cases had been recorded in Alberta, where authorities reported one influenza-related death involving a person aged 70-79 in the Calgary area.

Brian Ward, professor emeritus at the Research Institute of the McGill University Health Centre in Montreal, said H1N1-dominated seasons can produce substantial outbreaks without the same proportion of severe illness seen in seasons dominated by H3N2.

"So far at least, this looks like an H1N1 dominated year, and the years where H1N1 dominates, you can have very large outbreaks, but the number or the proportion of people … who get very sick, is relatively small compared to years that are dominated by H3N2," Ward told CBC News.

Ward cautioned that the available Canadian evidence did not yet establish a widespread outbreak.

"I'm not convinced yet that we're actually seeing the beginning of a real outbreak. What we're seeing is sort of isolated, small outbreaks."

He said influenza activity remained limited across much of Canada, despite increases in British Columbia, Yukon, Toronto and Calgary.

"The rest of the country is really very quiet," Ward said.

Ward also warned that gatherings during Canada's Thanksgiving weekend could accelerate transmission, particularly following outbreaks in long-term care homes in British Columbia.

"That may be the seed that moves the virus … into the schools and universities and marketplaces and so on. But overall, we're still below the 5 per cent [epidemic] threshold."

In Toronto, family physician Joseph Param told CBC News that he had recently treated an increasing number of patients with significant symptoms, including otherwise healthy young adults.

"Over the last couple of weeks, patients who are very healthy who see me rarely have been coming in with severe symptoms," Param said.

He emphasized the importance of recognizing the earlier timing of influenza activity.

"So it is important that the general population is aware that we are seeing … early cases now and so that we start taking precautions earlier than expected."

California has also experienced an earlier-than-usual start. The Los Angeles County flu season began September 28, according to the Los Angeles Times, compared with the area's typical early-November start. State figures cited by the newspaper recorded 34 influenza-related deaths across California so far this season, while Los Angeles County had reported none at the time of publication.

Dr. Dawn Terashita, associate director of Los Angeles County's Acute Communicable Disease Control Program, said influenza patterns can change unpredictably because the virus mutates. She noted that an early start alone does not establish that the season will be more severe.

Dr. Elizabeth Hudson, regional chief of infectious diseases at Kaiser Permanente Southern California, said the early increase might have caught people before vaccination had time to provide protection. The organization had observed more flu-related outpatient visits, although hospitalizations had not yet increased.

Dr. Peter Chin-Hong, an infectious disease expert at UC San Francisco, said the current H3N2 subclade K appears similar to last year's strain and is included in the 2026-27 vaccine. He encouraged people to seek vaccination before influenza circulation becomes more widespread.

"The ball is in our court because vaccination behavior drives how we tackle the flu," Chin-Hong said.

Terashita said health officials were continuing to monitor the season's development while emphasizing the value of immunization.

"We're just watching and waiting right now" to see how severe the season will be, she said, "but it is a good reminder to everyone that it's a very good thing you can do to protect yourself, which is get the vaccine."

In the United States, the Centers for Disease Control and Prevention recommends annual influenza vaccination for everyone aged 6 months and older, unless a medical contraindication applies. Public health specialists generally advise vaccination during September or October, while emphasizing that immunization can still be useful later in the season as influenza viruses continue circulating.

Dr. Michael Angarone, director of the Infectious Disease Fellowship Program at Northwestern University Feinberg School of Medicine, highlighted the importance of vaccination for people at elevated risk of complications.

"Obviously, we target high-risk groups, so those would be older adults, so over the age of 50, people with chronic medical conditions, individuals who are immunocompromised, individuals that have obesity, or persons who are pregnant or wanting to get pregnant, and healthcare personnel," Angarone told ABC News.

He also recommended vaccination for patients who do not fall into those higher-risk categories.

"But I recommend every patient that I see should get vaccinated for influenza."

Available vaccines include standard-dose injections, enhanced formulations for adults aged 65 and older, cell-based vaccines, recombinant vaccines and a nasal spray option for eligible people aged 2-49. In August 2026, the Food and Drug Administration approved Moderna's mRNA influenza vaccine for adults aged 50 and older.

Dr. Majd Alsoubani, an infectious disease physician at Tufts Medical Center, addressed a common misconception about influenza vaccination.

"All the injectable influenza vaccines, they don't have the live virus, it only contains parts of the virus, so it doesn't cause influenza," Alsoubani told ABC News.

She explained that immunity does not develop immediately after vaccination.

"We know that the vaccine needs a couple of weeks just to create protection, so if they were exposed to influenza before the vaccine or right after, they actually might get the flu because the vaccine didn't have time to provide that protection."

Angarone said eligible patients can receive their influenza and COVID-19 vaccines during the same appointment.

"I recommend to my patients just get it at the same time, or if you don't want to get both at the same time, get [the COVID vaccine] a week apart from the flu vaccine," he said.

He added that October was an appropriate time to arrange the vaccinations.

"So, kind of around this time, October timeframe."

Updated COVID-19 vaccines for the 2026-27 season target the XFG Omicron recombinant variant. The CDC recommends vaccination for adults aged 18 and older and for children aged 6 months through 17 years who are at increased risk, with recommendations depending on age, health conditions and vaccine eligibility.

RSV prevention is another priority during respiratory virus season. Alsoubani said vaccination recommendations focus on people at elevated risk of severe illness.

"The immunization recommendation kind of follows the people who are at risk of severe disease," Alsoubani said.

She noted that the adult RSV vaccine is administered as a single dose rather than an annual vaccination.

"So the RSV vaccine currently is only one dose, so you're one and done. It's not an annual vaccine."

The CDC recommends RSV vaccination for adults aged 75 and older, adults aged 50-74 at increased risk of severe disease, and pregnant people between 32 and 36 weeks of gestation. Certain infants and young children may also qualify for preventive monoclonal antibodies, depending on age, maternal vaccination history and medical risk.

Experts stress that the early rise in influenza activity does not, by itself, predict the season's eventual severity. The CDC's outlook for the 2026-27 respiratory virus season anticipates peak hospitalization levels for influenza, COVID-19 and RSV comparable to those of the previous season.